Kentaro begins the story as grade-school-aged brat, generally seen trying to get between his mother and her bottle. Initially, he is antagonistic toward Yusaku, but events soon see him to look upon Yusaku as an "alright guy." He is also very fond of Kyoko, especially because he sees her as the one of sane person in the building. He develops a crush on Kyoko's niece Ikuko, reminding Yusaku of himself, although Kentaro resents the comparison.